Smothers was charged as an adult and pleaded guilty to one count of aggravated assault while armed back in October. Following his prison term, he will be placed on five years of supervised release.

"When parents send their kids off to school, they should never have to worry that their child could be caught in a hail of gunfire during the school day," said U.S. Attorney Ronald C. Machen Jr. on Friday. "Our decision to charge this shooter as an adult is a reflection of how seriously we take gun crimes in the District and how committed we are to keeping our schools free of gun violence."

Both Smothers and the 18-year-old victim were students at the school at the time of the shooting Sept. 19.

Authorities say there was a verbal altercation between the two that day, and Smothers returned to the school after dismissal and confronted the other student, showing him a gun.

The victim attempted to shield other students from the gunfire and was shot in the leg. Police saw Smothers running from the scene and stopped him in the 100 block of Rittenhouse Street NW.

The school building was locked down as a precaution to protect those students still in the building after hours.

"I got scared.... It just came out of the blue," said student Jazzlyn Hill, who was inside during the lockdown.